It is known from U.S. Pat. No. 4,507,245 to react a rare earth metal alkoxide and an alkali metal alkoxide in an inert organic solvent under anhydrous conditions to yield a rare earth alkoxide of the formula (MOR).sub.3 where M is a rare earth metal and R is an alkyl group. Such alkoxides contain a single metal atom.
Certain disclosures also exist in the art in regard to producing products containing a metal atom, alkoxide moieties and the trimethylsilyl moiety (R.sub.3 SiO). Such products are formed by reacting a metal alkoxide with the covalent compound trimethylacetoxysilane and are disclosed in D. C. Bradley, J. Chem. Soc., 3404-3411 (1957); P. P. Sharma et al., Indian J. Chem., Vol. 5, September 1967, 456-457; R. C. Mehrotra et al., J. Indian Chem. Soc., Vol. 44, No. 3, 1967, pp. 223-224; R. C. Mehrotra et al., J. Indian Chem. Soc., Vol. 44, No. 4, 1967, pp. 345-346; and J. M. Batwara et al., J. Inorg. Nucl. Chem., 1970, Vol. 32, pp. 411-415.
Aluminum sec-butoxide was reacted with acetic acid as described by A. Ayral et al., J. Mater. Res., Vol. 4, No. 4, 1989, pp. 967-971. Sec-butyl alcohol was detected as a product initially, followed by sec-butyl acetate ester. This led the authors to propose an intermediate structure containing aluminum monobutoxide-diacetate which formed a basic acetate upon hydrolysis. Titanium (IV) butoxide was reacted with glacial acetic acid to obtain a titanyl-acrylate-type precursor, Ti n-(OBu).sub.3 (OAc), with the liberation of butanol. The chemical reactivity of the precursor was less than the parent alkoxide as claimed by C. Sanchez et al. in "Ultrastructure Processing of Advanced Ceramics", J. D. Mackenzie and D. R. Ulrich, eds., Wiley, New York, 1988, p. 77. Upon hydrolysis with water, the butoxide was removed while the acetate remained bonded to the titanium. In both cases, the authors did not separate or identify the intermediate they produced. This disclosure relates to use of a single alkoxide reagent.
Other condensation products have been reported (i.e., in U.S. Pat. No. 2,621,193) where titanium alkoxides are reacted with organic acids to get mixed alkoxide-carboxylate compositions of a single metal, for example, titanium.
U.S. Pat. No. 4,122,107 to J. F, Kenney discloses catalysts which are the reaction products of specific antimony or zirconium (IV) compounds with a carboxylate of calcium, manganese or zinc and an acid anhydride, alcohol, or glycol. Col. 3, lines 46-47 indicate that the product is a bimetallic alkoxide "or" carboxylate. Bimetallic alkoxide-carboxylate compositions are not disclosed.
M. Osgan et al. in Polymer Letters, Vol. 88, pp. 319-321 (1970) describe previous work reported in U.S. Pat. No. 3,432,445 dealing with condensation products of certain bivalent metal compounds (e.g., zinc acetate) as catalysts and trivalent metal compounds (e.g., aluminum alcoholates) and indicate that the proposed species (i.e., mu-oxo-alkoxides of aluminum and zinc) were not formed but that the condensation products contained some residual acetato groupings and some higher condensed species. Osgan et al. therefore proposed to form the desired condensation products by "some other independent way", namely, by the controlled hydrolysis of aluminum and zinc alkoxides under alcoholysis conditions.
In related U.S. Ser. Nos. 534,824 and 552,633 filed Jun. 7, 1990 and Jul. 13, 1990, respectively, mixed heavy bimetallic alkoxide-carboxylate compositions are formed which comprise reacting a heavy metal alkoxide and another heavy metal carboxylate under substantially anhydrous conditions with the elimination of distillable ester by-product therefrom. The products from this reaction can be used as a raw material for forming mixed metal oxides when fired. In cases in which a stable, isolated heavy metal carboxylate is not readily available, however, a need has arisen for a modified procedure to form such mixed alkoxide-carboxylate products. It is to this specific need that the present invention is addressed.